Electrochemical gold-separator



H. P. EWELL.

ELECTROCHEMICAL GOLD SEPARATOR.

APPLICATION FILED NOV. 7, 1913.

1,374,370. Patented Apr. 12, 1921.

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APPLICATION FILED NOV. 7. 1918.

1,374,370. Patented Apr. 12, 1921.

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ELECTROCHEMICAL GOLD SEPARATOR.

APPLICATION FILED Nov, 7, 1918.

1,374,370, Patented Apr. 12, 1921.

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ELECTROCHEMICAL GOLD SEPARATOR.

APPLICATION FILED NOV. 7, 1918.

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Patented Apr. 12, 1921.

814mm fferierz PZweZZ H. P. EWELL.

ELECTROCHEMICAL GOLD SEPARATOR.

APPLICATION FILED NOV. 7, 1918.

1,374,370. Patented Apr. 12, 1921.

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PATENT OFFICE.

HERBERT P. EWELL, OF LOS ANGELES, CALIFORNIA.

ELECTROCHEMICAL GOLD-SEPARATOR.

Specification of Letters Patent.

Patented Apr. 12, 1921.

Application filed November 7, 1918. Serial No. 261,443.

To all whom it may concern:

Be it known that I, HERBERT P. EWELL, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented a new and useful Electrochemical Gold-Separator, of which the following is a specification.

This invention relates to electro-chemical gold separators, and is designed to accomplish the separation of fine gold from silts and fine placer sands, though it may be used advantageously in the separation of any free gold or silver from the ore thereof, or for recovering floured mercury from mill tailings.

It is the object of the invention to provide an amalgamating apparatus having provision for electro-chemically forming liquid sodium amalgam in a chamber by itself, the electrolyte in said chamber being maintained at a constant density to insure a uniform composition for the sodium amalgam, such as is best adapted for the work in hand.

Another object is to so distribute the sodium amalgam and the ore pulp to a series of copper plates as to maintain a complete contact between said amalgam and pulp, and at the same time insure a constant nascent condition within the area where this contact occurs.

A further object is to provide a gold separator having a large capacity as compared to the floor space it requires, thus especially adapting the machine for use on a dredge deck Where the available floor space is not ordinarily great enough to accommodate sufficient amalgamating units to treat all -of the fine sands and silts that the bucket line of the dredge is capable of handling.

In attaining these objects, the invention contemplates providing for the continuous supply of ore pulp to a series of suitable gold amalgamating chambers formed between copper plates, and for the even distribution to said chambers of liquid sodium amalgam continuously formed in another chamber, the tailings being separated from the gold amalgam and surplus mercury by means of a shaking pan and the mercury being returned by a suitable pump to the chamber in which the sodium amalgam is formed.

A preferred embodiment of the invention is disclosed in the accompanying drawings, wherein:

Figure 1 is a plan view of a machine embodying the invention.

Fig. 2 is a view of the same in side elevation.

Fig. 3 is a longitudinal vertical sectional view taken on line 3'3 of Fig. 1.

Fig. 4 is a transverse vertical sectional View taken on line 4-4 of Fig. 1.

Fig. 5 is a fragmentary plan view of the perforated plates through which the liquid sodium amalgam is distributed between a series of underlying copper plates, said perforated plates being sufiiciently broken away in the figure to disclose a number of said copper plates.

Fig. 6 is a vertical sectional view of the same, the section being taken on line 66 of F ig. 5.

Fig, 7 is a vertical sectional view of the receiving chamber for the gold amalgam, showing in detail the pocket valve mechanism for intermittently admitting the amalgam to said chamber.

In these views the reference character 1 designates a supporting frame constructed primarily of angle bars, said frame having a relatively low portion supporting the shaking pan 2, a rocker arm 2 being pro vided beneath each corner of said pan, and having a higher portion supporting apparatus for forming the sodium amalgam and distributing the same to the ore pulp. The latter is supplied to the machine by the feed launder 3 and initially enters an opentopped chamber 4 having the bottom thereof perforated as indicated at 5. These perforations insure a substantially uniform distribution of the ore pulp into a launder 6 which is inclined slightly to discharge the pulp between the upper end portions of a series of zig-zag copper plates 7. Walls 8 are provided at each side of this series of plates so that the pulp is constrained to flow tortuously downward through the restricted amalgamating chambers 9 formed between said plates. These chambers terminate above one end of the shaking pan 2, which end is slightly lower than the other.

The sodium amalgam is formed in a chamber 10 by the electrolytic decomposition therein of sodium chlorid in solution. One of the electrodes immersed in said solution is formed by a plurality of carbons 11 suspended in the upper portion of said chamber and the other is formed by a layer maintain the same constantly at the satura and as the two of mercury 12 in the bottom partof the chamber, said electrodes deriving current scribed mechanism for constantly driving the same so as to agitate the solution and tion point. Upon decomposition of the sodium chlorid, due to passage of an electric current therethrough, the chlorin passes off and the sodium unites with the mercury to form an amalgam. As a provision for agitating the mercury so as to facilitate its union with the sodium, there is mounted a spider wheel 15 in the bottom portion of the chamber 10, which Wheel is adapted to be constantly driven as hereinafter explained. The water in the chamber 10 and tank 13 may be maintained at a constant level in various well known ways, as for example by a float valve.

A discharge for the sodium amalgam is provided through a pipe 16 communicating with the bottom of said chamber and upwardly return-bent exterior to the chamber as indicated at 17 to insure the maintenance of a proper mercury level within the chamher, a vent pipe 18 being in communication with said pipe at the bend 17 to prevent siphoning. The pipe 16 discharges into a pipe 19 extending transversely of the launder 6 above the same, and the liquid sodium amalgam escapes from said pipe through a plurality of flexible tubes 20, discharging at various points within a trough 21, extending above the series of plates 7. Between the bottom 22 of said trough and the upper ends of the. plates 7 there .is mounted a plate 23 which is reciprocatory longitudinally of said trough, said plate and the trough bottom being each formed with a series of perforations 24 which are alternately shifted into and outof registration by reciprocation of said plate, thus providing for an intermittent escape of the liquid sodium amalgam from the trough 21 1nto the spaces between the plates 7. A mechanism for actuating the plate 23 and also for riciprocating the free ends of the tubes 20 will presently be described.

Within the restricted chambers formed between the plates 7 the liquid sodiumamalgam encounters the ore pulp which is being constantly introduced into the upper portions of said passages from the launder 6, pass downwardly together the amalgam completely permeates the ore pulp, coming into contact with all the particles of gold therein and uniting with the the shaking pan into a well 28, thus providing for discharge of the gold amalgam and free mercury. A flexible pipe 29 drains the well 28, conducting the contents thereof to a settling tank 30, wherein the gold amalgam since it is heavier than the mercury displaces the latter to the upper portion of the tank. Beneath said tank is located a receiving chamber 31 for the gold amalgam, an intermittent discharge of the amalgam from the tank 30 to said chamber being provided for by a pocket valve 32, which is subjected to a step by step rotation by means presently to be described. 33 designates a lock preventing access to the chamber 31 except by authorized persons. The mercury in the upper portion of the tank 30 discharges by gravity through a flexible pipe 34 into the barrel of a pump 35, said pipe having an intermediate portion vertically adjustable by means of a fastening 36 for the purpose of regulatingthe level of mercury in the well 28. The plunger of the pump 35 extends upwardly as indicated at 37, being actuable by a mechanism presently to be described. The barrel of the pump is' surmounted by a pan 38 which catches any mercury that may drip from the plunger 37 and returns it by way of a pipe 39 to the pump; said pipe having a trap 40 therein to prevent the passage of any matter lighter than mercury, therethrough. The pump 35 discharges into a pipe 41 and thence into the sodium generating chamber, so that the excess of mercury is thus continuously returned to said cham- Describing now the driving mechanism for the various parts, 42 is a shaft mounted transversely beneath the shaking pan and having upon one end thereof a driving pulley 43. At the other end of said shaft a driving connection is established to a shaft 44 extending along side of the shaking pan by a pair of bevel gears 45. The shaft 44 carries a pair of.eccentrics 46 from which pitmen 47 are extended to the shaking pan for rocking the latter.

A chain 48 engaging sprocket wheels 49 and 50 transmits rotation from the shaft 44 to a shaft 51 mounted upon the raised por- .tion of the frame 1, and thence rotation is transmitted by a air of gears 52 to an adjacent shaft 53. pon the last mentioned shaft there is mounted an eccentric 54 with which are connected two pitmen 55 respectively actuating slide bars 56 and 57 transversely extending above the launder 6. The bar 56 is engaged with the free ends of the flexible tubes 20 so that said ends are reciprocated to vary the points of discharge, and the bar 57 is pivotally engaged by the arms 58 of a series of bell cranks mounted in bearings 59 upon a wall of the trou h 21, the other arms 60 of said bell-cranks Teing pivotally connected to the plate 23. Thus through said bell cranks a reciprocating motion transverse to that of the bar 57 is transmitted from said bar to the plate 23. To guide said plate in this motion it is formed at its edges with upturned flanges 61 which engage grooves 62 in the bottoms of brackets 63, one of which is arranged at each end of the trough 21 and is bolted thereto as indicated at 64. The outlets from said trough jointly provided by the orifices 24: in the members 22 and 23 may be more or less restricted by adjusting the bolts 64 to shift the plates 22 and 23 relatively so as to increasingly or decreasingly register the orifices 24 of said plates. To assist in maintaining any desired position of relative adjustment, bolts 65 are also mounted in the brackets 63 with their ends abutting against the end walls of the trough 21.

The shaft 51 carries at one end thereof a crank disk 66 from which a connecting rod extends to the pump plunger 37 for actuating the pump. To intermittently rotate the pocket valve 32, the stem 67 of said valve carries a flan ed disk 68 exterior to the chamber 31 and a so has loosely pivoted thereon adjacent said disk an arm 69 which carries a friction pawl 70 grooved at 71 to engage the flange of the disk 68. From the end of said arm 69 a pitman 72 is extended upward to be actuated by an eccentric 73 upon the shaft 53, an oscillatory movement thus being communicated to the arm 69. Each time that said arm is raised the pawl 70 grips the flange of the disk 68, rotatively actuating the same and the pocket valve 32, so that a gradual step by step movement is imparted to said valve.

To drive the paddle wheel 14: and spider wheel 15, a shaft 74 is mounted above the v chamber 10 and tank 13, and is driven through a chain and sprocket wheel mechanism 75 from the shaft 53. Said paddle wheel and spider wheel are respectively mounted upon shafts 76 and 77 extending centrally upward through the receptacles 13 and 10 driven from the shaft 74 by pairs of bevel gears 78 and 79.

The gold amalgam may be removed from time to time from the chamber 31, retorted to extract the gold, and the mercury returned to the chamber 10.

The extremely active and positive contact between the ore pulp and the amalgamating material that takes place in the chambers 9, and the large capacity attainable, render the above described separator Well suited for the working of the large deposits of lowgrade auriferous fine sands and silts by the use of dredges at a handsome profit.

It will be readily understood that the invention may be built in any desired width, and that any machine already built may have its capacity decreased if desired by placing partitions through the several compartments where necessary. Also even although the machine may be thrown out of level, a perfectly uniform distribution of the sodium amalgam may be maintained by placing a suitable number of partitions across the trough 21 to prevent the contents from runnin to the lower end.

The "tanks 10 and 13 are properly insulated to prevent grounding of the current; and to protect said tanks from the chemicals which they contain, they are preferably interiorly coated with porcelain.

It will be noted that the plates 7 have inclined tongues formed at their upper ends. These tongues function to receive the liquid sodium amalgam as it drips through the orifices 24 causing it to flow down the walls of said plates. The angles in the plates as they deflect the descending ore pulp also establish a positive contact between the pulp 100 and the liquid amalgam flowing upon the angular portions of the plates so that by the provision of a sufficient number of said angles a complete contact of the entire de scending mass with the amalgam is assured without requiring a large surplus of the amalgam.

What I claim'is:

1. In a gold separator, the combination with a gold amalgamating chamber and means for continuously feeding ore pulp into said chamber, of a chamber for forming liquid sodium amalgam, means for continuously supplying the liquid amalgam from the last named to the first named chamber, a shaking pan receiving the gold amalgam, surplus mercury and tailings from the gold amalgamating chamber, a well draining the gold amalgam and mercury from said pan, means for separating the gold amalgam from the mercury, and means for returning the mercury to the chamber in which sodium amalgam is formed.

2., In a separator, the combination with a gold amalgamating chamber, of means for continuously feeding ore pulp to said chamber, a trough extending above said chamber, having a plurality of outlets into said gold amalgamating chamber, a plurality of PIPES. for discharging liquid sodium amalgam into said trough, and means for simultaneously oscillating the discharge ends of said pipes longitudinally of said trough.

3. In a separator, the combination with a gold amal amating chamber, of means for continuous y feeding ore pulp thereto, a trough extending above said chamber having a perforated bottom, a plurality of pipes for discharging sodium amalgam into said chamber, means for simultaneously oscillating the discharge ends of said pipes, a plate adjacent the bottom of the trough hav ing perforations therein corresponding to those in the trough bottom, means for reciprocating said plate to shift the perforations thereof into and out of registration with those of the trough bottom, a shaking pan upon which the gold amalgamating chamber discharges its contents, and means for draining the gold amalgam and surplus mercury from said pan.

4. In a separator, the combination with a gold amalgamating chamber and means for continuousl feeding ore pulp into said chamber, 0 a chamber for the production of sodium amalgam, means for supplying sodium amalgam from said last named to the first named chamber, a shaking pan upon "which the gold amalgamating chamber discharges, a well draining the gold amalgam and surplus mercury from said pan, a settling chamber draining said well, and means for returning mercury from said well to the chamber in which sodium amalgam is formed.

5. In a separator, the combination with a series of spaced zigzag bars forming substantially vertical passages therebetween, of means for continuously feeding ore pulp between the upper end portions of said bars, means for producing a uniform'discharge of a liquid amalgam between'the upper ends of said bars, a shaking pan beneath said bars upon which pan said vertical passages discharge their contents, and means for draining off the gold amalgam and surplus mercury from said pan.

In testimony whereof I sign this specification.

HERBERT P. EWELL. 

